Add common languages SDKs by sebastienros · Pull Request #13978 · dotnet/aspire

sebastienros · 2026-01-16T23:54:21Z

Description

Adds Python, Go, Java and Rust polyglot apphost support.

Currently in Draft to test the CI.

Checklist

Is this feature complete?
- Yes. Ready to ship.
- No. Follow-up changes expected.
Are you including unit tests for the changes and scenario tests if relevant?
- Yes
- No
Did you add public API?
- Yes
  - If yes, did you have an API Review for it?
    - Yes
    - No
  - Did you add <remarks /> and <code /> elements on your triple slash comments?
    - Yes
    - No
- No
Does the change make any security assumptions or guarantees?
- Yes
  - If yes, have you done a threat model and had a security review?
    - Yes
    - No
- No
Does the change require an update in our Aspire docs?
- Yes - Add polyglot AppHost documentation for TypeScript, Python, Go, Rust, … microsoft/aspire.dev#277
- No

This commit adds code generation support for Go and Java AppHosts: Go Code Generator (Aspire.Hosting.CodeGeneration.Go): - AtsGoCodeGenerator.cs: Generates Go SDK wrapper code from ATS capabilities - GoLanguageSupport.cs: Provides scaffolding, detection, and runtime config - Resources/transport.go: JSON-RPC client with Windows named pipe support - Resources/base.go: Base types (HandleWrapperBase, ReferenceExpression, etc.) Java Code Generator (Aspire.Hosting.CodeGeneration.Java): - AtsJavaCodeGenerator.cs: Generates Java SDK wrapper code with camelCase naming - JavaLanguageSupport.cs: Provides scaffolding, detection, and runtime config - Resources/Transport.java: JSON-RPC client with Windows named pipe support - Resources/Base.java: Base types for handle wrappers Both generators: - Generate wrapper classes that proxy capabilities via JSON-RPC - Support enums, DTOs, and handle types from ATS context - Include registration helpers for handle wrapper factories - Generate connection helpers (Aspire.Connect(), Aspire.CreateBuilder()) CLI Integration: - Register Go and Java in DefaultLanguageDiscovery.cs - Add language constants to KnownLanguageId.cs - Add code generator assemblies to AppHostServerProject.cs - Add InternalsVisibleTo entries in Aspire.Hosting.csproj - Add projects to Aspire.slnx

This commit adds initial Rust code generation support for AppHosts: Rust Code Generator (Aspire.Hosting.CodeGeneration.Rust): - AtsRustCodeGenerator.cs: Generates Rust SDK wrapper code with snake_case naming - RustLanguageSupport.cs: Provides scaffolding, detection, and runtime config - Resources/transport.rs: JSON-RPC client with Windows named pipe support - Resources/base.rs: Base types for handle wrappers The generator produces: - Enum types with serde Serialize/Deserialize derives - DTO structs with optional field support - Handle wrapper structs that proxy capabilities via JSON-RPC - Connection helpers (connect(), create_builder()) CLI Integration: - Register Rust in DefaultLanguageDiscovery.cs - Add language constants to KnownLanguageId.cs - Add code generator assembly to AppHostServerProject.cs - Add InternalsVisibleTo entry in Aspire.Hosting.csproj - Add project to Aspire.slnx Note: This is a work-in-progress. The generated Rust code compiles the infrastructure but needs further refinement for full AppHost functionality. The handle wrapping pattern needs adjustment for Rust's ownership model.

- Add serde Serialize/Deserialize derives to ReferenceExpression in base.rs - Fix DTO property serde attributes to only use skip_serializing_if for optional fields - Exclude ReferenceExpression from IsHandleType check - Add special handling for CancellationToken, AspireDict, AspireList return types - Update CancellationToken to support both local and handle-backed modes The generated Rust code now compiles successfully with cargo build.

…pendencies runs before code generation, so it cannot compile generated code. Moved compilation to Execute step for both Java and Rust. - Make Rust parameters idiomatic: String parameters now use &str instead of String, which is more idiomatic Rust.

- Remove InstallDependencies (go run handles dependencies automatically) - Add 'require' directive to go.mod (needed alongside 'replace' directive)

github-actions · 2026-01-16T23:54:37Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 13978

Or

Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 13978"

…rators

- Added 19 tests covering: - Language property returns Python - Embedded resources (transport.py, base.py) match snapshots - Generated code includes expected capabilities - Method names derive correctly - Parameters are captured correctly - ReturnsBuilder is set for fluent chaining - Scanner metadata verification via Verify snapshots - Two-pass scanning merges types from all assemblies - Generated code uses snake_case method names - Generated code has create_builder function - Generated code uses Python type hints - Shares TestTypes with TypeScript tests via Compile Include - Added Verify.XunitV3 for snapshot testing - All tests pass

- Go: 19 tests with snapshot verification for generated code - Java: 19 tests with snapshot verification for generated code - Rust: 19 tests with snapshot verification for generated code - Tests follow the TypeScript test project pattern with shared TestTypes - Uses Verify.XunitV3 for snapshot testing

… Rust Following the TypeScript improvements in main for List properties on context classes, this commit applies the same pattern to all other language generators: - Add lazy handle resolution to AspireList and AspireDict classes - Generate cached property getters for List/Dict type properties - Context classes now create AspireList/AspireDict with getter capability ID - The handle is resolved lazily on first access This ensures consistent behavior across all polyglot code generators when accessing List/Dict properties on [AspireExport(ExposeProperties=true)] types.

davidfowl · 2026-01-17T04:41:53Z

🐛 Go SDK Code Generation Error

Tested with CLI version 13.2.0-pr.13978.gb4f81399

Command

aspire sdk generate path/to/Aspire.Hosting.csproj --language go --output ./go-sample

Error

System.MethodAccessException: Attempt by method 
Aspire.Hosting.CodeGeneration.Go.AtsGoCodeGenerator.GenerateHandleWrapperRegistrations(...) 
to access method Aspire.Hosting.Ats.AtsConstants.IsDict(System.String) failed.

Stack Trace

at AtsGoCodeGenerator.GenerateHandleWrapperRegistrations(...) in AtsGoCodeGenerator.cs:line 372
at AtsGoCodeGenerator.GenerateAspireSdk(AtsContext context) in AtsGoCodeGenerator.cs:line 89
at AtsGoCodeGenerator.GenerateDistributedApplication(AtsContext context) in AtsGoCodeGenerator.cs:line 36
at CodeGenerationService.GenerateCode(String language) in CodeGenerationService.cs:line 162

Root Cause

The Go code generator is calling AtsConstants.IsDict() which appears to be internal in Aspire.Hosting.Ats. The Go codegen assembly does not have access.

Suggested Fix

Add [InternalsVisibleTo("Aspire.Hosting.CodeGeneration.Go")] to Aspire.Hosting.Ats, or make IsDict()/IsList() public.

mitchdenny · 2026-01-17T05:17:37Z

@copilot in the Python polyglot E2E CLI test you need to enably polyglot support via the feature flag. Review the typescript E2E for an example.

Copilot · 2026-01-17T05:17:49Z

@mitchdenny I've opened a new pull request, #13981, to work on those changes. Once the pull request is ready, I'll request review from you.

…generators Replace calls to internal AtsConstants.IsDict()/IsList() methods with AtsTypeCategory checks. The internal methods caused MethodAccessException when assemblies were dynamically loaded at runtime. - Go, Python, Java generators now use Dictionary<string, bool> to track whether each collected type ID is a Dict or List - Category is determined at collection time using AtsTypeCategory enum - Fixes runtime error: MethodAccessException when accessing internal methods

Remove the 'aspire run' step from the E2E test since Python runtime may not be available on CI. The test now only verifies: - Creating a Python apphost with 'aspire init -l python' - Adding Redis integration with 'aspire add redis'

Verify that generated files contain expected code: - apphost.py contains create_builder import and usage - .modules/aspire.py contains add_redis method after adding Redis integration

# Conflicts: # .github/workflows/cli-e2e-recording-comment.yml

- Use 'aspire run --detach' instead of timeout with background process - Use 'aspire stop' for cleanup instead of kill - Add polling loop (12 attempts x 10s = 2 min, 18 for Rust = 3 min) - Keep --non-interactive flag on aspire add command

.github/workflows/polyglot-validation/test-go.sh

- Use 'aspire run --detach' instead of timeout with background process - Use 'aspire stop' for cleanup instead of kill - Add polling loop (12 attempts x 10s = 2 min, 18 for Rust = 3 min) - Keep --non-interactive flag on aspire add command # Conflicts: # .github/workflows/polyglot-validation/test-go.sh # .github/workflows/polyglot-validation/test-java.sh # .github/workflows/polyglot-validation/test-python.sh # .github/workflows/polyglot-validation/test-rust.sh

The save_global_settings call for channel can fail in some container environments. Since the workflow explicitly sets the channel config afterward, this failure should not be fatal.

When --non-interactive flag is passed and there are multiple packages or versions to choose from, auto-select the first one (latest version) instead of trying to prompt and throwing an exception.

This ensures the workflow uses the script from the current branch/PR, which includes fixes for non-fatal config set errors.

Run aspire run in background with &, poll for Redis container, then kill the process on cleanup. Also capture aspire.log on failure for debugging.

The native AOT Aspire CLI requires GLIBC 2.38 which is only available in Debian 13 (trixie), not Debian 12 (bookworm).

…lotJavaTests These are replaced by the polyglot-validation workflow which runs SDK validation in Docker containers.

Start aspire run in its own process group with setsid, then kill the entire group with kill -9 -$PID to ensure all child processes are terminated.

davidfowl · 2026-01-22T08:33:51Z

Would it be cleaner to build docker files for each scenario

- Create Dockerfile.python, Dockerfile.go, Dockerfile.java, Dockerfile.rust, Dockerfile.typescript - Update polyglot-validation.yml to build and run Dockerfiles instead of inline scripts - Improves maintainability and enables easier local testing

radical · 2026-01-22T17:59:45Z

/azp run aspire-tests

azure-pipelines · 2026-01-22T17:59:59Z

Azure Pipelines successfully started running 1 pipeline(s).

sebastienros · 2026-01-22T20:35:55Z

@radical why did you break my build?

radical · 2026-01-22T20:37:01Z

/ba-g known failures

radical · 2026-01-22T20:37:37Z

@radical why did you break my build?

Just making sure it didn't break on azdo. It's green to merge now.

annatisch · 2026-01-22T23:31:01Z

src/Aspire.Cli/Commands/AddCommand.cs

        }

-            // ... otherwise we had better prompt.
+        // In non-interactive mode, auto-select the latest version.


omg thank you this was driving me nuts....

Meir017 · 2026-01-24T17:25:05Z

.github/workflows/polyglot-validation/test-go.sh

+
+# Add Redis integration
+echo "Adding Redis integration..."
+aspire add Aspire.Hosting.Redis --non-interactive 2>&1 || {


@sebastienros would this use the default docker registry? it might get rate limited.

That could be the case. To solve that we need to call .WithImageRegistry("netaspireci.azurecr.io") when we add AddRedis(...) in the apphosts. #14113

sebastienros added 8 commits January 15, 2026 18:28

Add python support

40e8537

Add go support

5759866

Fix Go code generator RuntimeSpec and module config

46ad57f

- Remove InstallDependencies (go run handles dependencies automatically) - Add 'require' directive to go.mod (needed alongside 'replace' directive)

Add E2E test

5865a70

sebastienros changed the title ~~Add common language SDKs~~ Add common languages SDKs Jan 16, 2026

sebastienros added 8 commits January 16, 2026 16:30

Fix named pipes for rust/java

adb0fae

Merge main - adopt additionalProjectReferences approach for code gene…

cffe834

…rators

Run PolyglotPythonTests as E2E

467ddf4

Move PolyglotPythonTests to correct E2E test folder for CI discovery

9cffcc0

Merge remote-tracking branch 'origin/main' into sebros/poly

5dbb4bd

Copilot AI mentioned this pull request Jan 17, 2026

Enable polyglot feature flag in E2E CLI tests #13981

Closed

10 tasks

sebastienros added 8 commits January 16, 2026 22:14

Enable polyglot support feature flag before init -l in E2E test

1ee5bb8

Simplify Python E2E test to not require Python runtime

cf6be2e

Remove the 'aspire run' step from the E2E test since Python runtime may not be available on CI. The test now only verifies: - Creating a Python apphost with 'aspire init -l python' - Adding Redis integration with 'aspire add redis'

Add file content verification to Python E2E test

e70b1d1

Verify that generated files contain expected code: - apphost.py contains create_builder import and usage - .modules/aspire.py contains add_redis method after adding Redis integration

Merge remote-tracking branch 'origin/main' into sebros/poly

82f21f8

# Conflicts: # .github/workflows/cli-e2e-recording-comment.yml

Add instructions

d4f50d7

Fix Python E2E test to handle version selection prompt in CI

443c51e

Fix Python E2E test pattern to match actual CLI output

600f52b

davidfowl reviewed Jan 22, 2026

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.github/workflows/polyglot-validation/test-go.sh Outdated Show resolved Hide resolved

sebastienros added 13 commits January 21, 2026 16:50

Make channel config setting non-fatal in get-aspire-cli-pr.sh

b9eecd9

The save_global_settings call for channel can fail in some container environments. Since the workflow explicitly sets the channel config afterward, this failure should not be fatal.

Fix aspire add --non-interactive to auto-select latest version

e115c18

When --non-interactive flag is passed and there are multiple packages or versions to choose from, auto-select the first one (latest version) instead of trying to prompt and throwing an exception.

Add -d flag to aspire run --detach for debug logging

762d7d6

Use local get-aspire-cli-pr.sh script instead of downloading from main

ca76992

This ensures the workflow uses the script from the current branch/PR, which includes fixes for non-fatal config set errors.

Use background job for aspire run instead of --detach

734040b

Run aspire run in background with &, poll for Redis container, then kill the process on cleanup. Also capture aspire.log on failure for debugging.

Use kill -9 and remove wait to prevent blocking on cleanup

1581358

Use go:1-trixie image for GLIBC 2.38 support

1e76779

The native AOT Aspire CLI requires GLIBC 2.38 which is only available in Debian 13 (trixie), not Debian 12 (bookworm).

Re-enable all tests that were temporarily disabled

e77122f

Add TypeScript polyglot SDK validation

7bfa895

Remove Base.verified.java, Transport.verified.java and their tests

f38a13c

Remove PolyglotPythonTests, PolyglotGoTests, PolyglotRustTests, Polyg…

73392bc

…lotJavaTests These are replaced by the polyglot-validation workflow which runs SDK validation in Docker containers.

Use setsid and kill process group to properly stop apphost

0ba21de

Start aspire run in its own process group with setsid, then kill the entire group with kill -9 -$PID to ensure all child processes are terminated.

sebastienros added 2 commits January 22, 2026 07:11

Add Redis in a consistent way across scripts

0b8cc23

davidfowl approved these changes Jan 22, 2026

View reviewed changes

annatisch reviewed Jan 22, 2026

View reviewed changes

sebastienros merged commit d1c3d6e into main Jan 22, 2026
325 of 329 checks passed

sebastienros deleted the sebros/poly branch January 22, 2026 23:42

dotnet-policy-service bot added this to the 13.2 milestone Jan 22, 2026

Meir017 reviewed Jan 24, 2026

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sebastienros mentioned this pull request Jan 24, 2026

Use test docker registry for polyglot sdk validation #14113

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🐛 Go SDK Code Generation Error

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